The Project Files series contains the records of twelve of the ACLU’s projects, which each addressed an area of civil liberties violations. Project records typically consist of case files, research files, project publicity correspondence. The best documented projects are the Children’s Rights Project Women’s Rights Project, to a lesser extent the Arts Censorship Project, Capital Punishment Project, Reproductive Freedom Project.

The Subject Files series contains articles, reports, court documents, and other materials collected by the ACLU during the course of their work. The main subjects are drugs, homelessness, and Supreme Court nominations, largely of Robert Bork. Other significant subjects in the series include campaign finance, discrimination, environmental equity and racism, school pension plans, state constitutions, and welfare.

The Legal Case Files series documents the ACLU’s involvement in litigation, ranging from files collected on cases for research purposes to records of cases they were significantly involved in. The records include documents filed with the court, correspondence, lawyer’s notes, depositions and expert testimony, transcripts of the trials, newspaper clippings, and research materials on the background of the case and legal precedent.

The Legal Case Files series contains records about over 1,500 cases, with the majority being files collected on non-ACLU cases for research on the broad range of civil liberties which the ACLU investigates. Common subjects include the separation of church and state, public education, racial and sexual discrimination, injustice in the legal system, illegal surveillance and search, and protecting the freedom of speech and expression, as well as politics and voting, information access and privacy, fair employment and health care practices, and immigration. Cases which are particularly well documented include Carlos Rivera v. John Rowland about the public defender system in Connecticut and three cases about public education: Brown v. Board of Education, Charlet v. Legislature of Louisiana, and Harper v. Hunt.